The present invention relates to a method for predicting the lifetime of a measured object by detecting the degree of deterioration of the measured object and an apparatus therefor.
If parts of machinery or products are defective, such as when they are cracked, hollowed or concaved, such parts may break. There is then the risk that a serious accident will take place when the defective parts fail. Therefore, the existence of such defective parts preferably should be detected and the parts eliminated before any machinery or products are assembled or fabricated from them.
Heretofore, nondestructive inspection methods are known that are effective in detecting the above-mentioned defects. Nondestructive inspection methods that are now available include an ultrasonic wave reflection method of detecting defects by using ultrasonic waves reflected from defective parts or defective products, a so-called AE (acoustic emission) method for detecting defective parts or defective products based on sounds generated when defective parts or defective products are cracked, a CCD (charge-coupled device) camera inspection method for inspecting the surface of defective parts or defective products, an X-ray photograph method and a color check method.
The above-mentioned inspection methods of detecting defects or the like can detect whether or not the measured object is defective, but cannot predict how long the measured object can be used safely, i.e., the lifetime of the measured object.
Parts of machinery and products progressively deteriorate in use. In the case of turbine blades used in a turbine engine, for example, it is important to be able to predict the lifetime of the turbine blades and to exchange a defective turbine blade with a new one in a proper period before the occurrence of defects to thereby prevent a serious accident from taking place.